So after Sworn to the Sword, the Rose Diamond theory is alive and well. Lots of stuff that went on. Some things that stood out to me (as well as others) include:

~ Pearl's loyalty and passion for Rose ("do it for her")~ Steven being 'very important' ("do it for him")~ Connie saying she knows Steven's destiny now~ The pink diamond included in the diamond formation with yellow, white, and blue~ The two crumbling/cracked diamonds at the sky arena~ The sky arena falling apart~ Pearl insisting that Steven shouldn't even be in battle (because he is so important)~ Training Connie to be Steven's "knight", much like how Pearl was a knight

I would like to add the the most expensive gem in the world was the Pink Star a pink diamond. And that the color of steven and rose's gem matches a pink diamonds better than a rose quartz.Now we know that the crewniverse are really good with hidden details. Another thing that brings this theory to life is that a Rose Quartz gem would fit the color pallet of the show better. (it's pastel and a pink diamond is a bright pink similar to stevens gem). Also in the background of Rose's flag their happens to be diamonds on it, but this could just be coincidence. Her dress is also very reminiscent ( i didn't notice this until story for steven) of Princess serenity (and her queen form) from sailor moon (a show we know influences su due to steven having a book of it in his room)My final argument for this, is that we see a lot of rose imagery, which could be just because she was so highly respected, but generally only nobility and royalty have imagery like Roses.I could sit here for days searching evidence up but I want other people to have some stuff to add.